Central-energy telephone system



No. 749,798. v PATENTED JAN. 19,1904.

K. B. MILLER. CENTRAL ENERGY TELEPHONE SYSTEM.

APPLICATION FILED DEO. 19. 1.900. N0 MODEL.

LT E l L m: onlus paens no. mormurnc.. vAsmuomu. n.-

UNITED STATES Patented January 19, 1904.

PATENT OFFICE.

KEMPSTER B. MILLER, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGGSWITCHBOARD AND SUPPLY COMBANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.`

CENTRAL-ENERGY TELEPHONE SYSTEN-I.

SPECIFICATION forming' part of Letters Patent No. 749,798, dated January19, 1904.

i Application Ied December 19, 1900. Serial No. 40,372. (No model.)

To all whom, t may concern:

Be it known that I, KEMISTER B. MILLER, a citizen ot' the United States,vresiding at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement `in Central-EnergyTelephone Systems, of which the followingV is afull, clear,

concise, and eXact description', reference being had to the accompanyingdrawings, forming a part of this specification. y My invention relatesto a central-energy telephone system, my object being to provide animproved form of telephone system wherein the source of current forenergizing the talking-circuits and the signaling apparatus a is locatedat the central station.

. view of a plug-seat switch.

the signaling device inert.

i I have Illustrated my invention In the aci My invention relates moreparticularly to the signaling apparatus at the central station by meansof which the subscriber signals the operator.

I have shown and described one specific embodiment of my invention forthe purpose of illi'istrating the generic principle underlying myinvention. 'In accordance therewith I provide a relay and a plug-seatswitch adapted to conjointly control the signaling device at the centralstation. I preferably arrange the relay so that the sameis energizedwhen the subscribers are connected for conversation, to thereby renderthe signaling device inert. In this manner the signaling device may beactuated to convey the signal for disconnection to the operator'by thehanging upofthe subscribers telephone-receivers. The return of theconnecting-plug to its seat serves to actuate the plug-seat switch andagain render companying drawings, in which- Figure l is a diagramshowing two subscribers telephone-lines and the central-stationconnecting apparatus. Fig. 2 is a detail gram showing thetalking-circuit. Fig. 4 is a view of a modified form of thesignaling-cirf cuit.

Like characters refer to like parts in the several figures. i

Fig. 3 is a diatact 2, which 'is connected through individualannunciator c' to conductor 3. The springs a2 anda'i carry armaturesresting opposite the poles of the relay-magnet and the spring a2 whenattracted is adapted to engage contact 4, which is connected withtheline-springs 0l d.

- rI`he spring a3 is adaptedwhen attracted to engage contact 5, which isconnected with` the sleeves (Z2 (Z2 of the spring-jacks d el. Movingwith the spring (L2, but insulated therefrom, is a'` spring connected toground through a resistance a5 and adapted when the relay is energizedto engage contact 6, which is connected with the test-rings d5. One endof the winding of relay b is connected with conductor 3, andA the otherend is connected with the contact-springs Z3 d3, which springsare-mounted to move'with but insulated frorn the line-springs d d',respectively. When the' 'plug is inserted in the spring-jack, theline-spring d is moved by the tip thereof 'to carry thel spring Z3 intoengagement with the grounded contact d4.

The subscriber is provided at the substation with the usual microphonef,receiver f', and swItch-hook f2, normally resting against contact 7,which is connected through bell f3 to ground. When the telephoneis'removed from the hook, the hook engages contact 8, which is connectedwith the telephoneftransmitter and receiver. The telephone-line B shownat `the right of the drawings is like the telephoneline A and isprovided with the same parts and mechanism, and like parts have beenindicated by the same reference characters employed in connection withthe line A.

vided with a tip o', connected with strand t', and with a sleeve ai,connected with a strand with the battery fr.

N'. rl`he strands are inductively united through windings of arepeating-coil w, said repeatingcoil comprising windings w 102,connected to the strands t and s, and windings w3 and @04, yconnectedbetween strands t' and s. A battery r is interposed between the windings'w' and Q02, and a battery/r is interposed between the windings w3 andwi.

A ringing-key g normally rests against contact 17 and is adaptedwhendepressed to engage contact 18, which is connected to ground throughgenerator g. rlhe operators telephone set 2,' is adapted to be bridgedbetween the strands t and s, and a condenser Z is included in circuittherewith to prevent the passage of the battery-current.

, 'lhe conductor 3, extending to a portion of the subscribers linescentering at the eX- ,change, is connected with one ypole of the batteryr, while the conductor 3, extending to the remaining' telephone-lines,is connected The opposite poles of thebatteries `r and apregrounded.`The plugs I y) and o normally rest in plug-seats, and plugseat switchesare provided adapted to be ac- ,tuated by the insertion of the plugs intheir.

respective seats and by the removal of the same therefrom. ATheanswering-plug pis adapted when inserted in its seat to separate thespring fm2 from contact 14, and likewise the plug o is adapted toseparate the spring o2 from contact 16.

1n circuit with the strand s is a relay-mag` -lposite the relay lf; is asimilar spring o, Anormally engaging contact 15. rlhe signaling- ".,lampviv/.is included in circuit with the battery vf and with thvecontacts ofrelay la and of the plug-seatswitch actuated by plug p. Likewise thelamp c" is included in circuit with the battery fr and with the contactsof the relay and of the plug-seat switch belonging to plug' o.

. l will now describe the manner in which the y subscribers areconnected together for conversation. Supposing subscriber A. desirous ofconversing-with subscriber B, he liftshis telephone -receiver .from itshook, thereby closing together limbs a and a at the substation andcompleting the circuit of .battery fr from ground over conductor 3,individual annunciator c, contact 2, spring a3, limb a,'limb a, springd?, contact 1,` to ground. The annunciator c is thus actuated, therebyattracting the attention of the operator, whoremoves the answering-plugpfrom its seat and inserts thesame 1n the spring-Jack belongingrtosubscriber. The insertion of the plug in the spring-jack moves springZ3 against contact d4, thereby energizing the relay b, the

circuit through said relay beingtraced from ground through battery r,conductor 8, relay b, spring (Z3, contact di, to ground. Therelay-magnet 7) upon being energized attracts the armatures carried uponsprings a2 and a3 and separates said springs, respectively, frorncontacts 1 and 2'and moves' the same against contacts' 4 and 5. Theindividual annunciator c is thus removed from circuit, and the terminalsof the spring-jacks are connected with the limbs of the telephone-line.rlhe circuit of battery r is now closed through relay 71, over strands sand and limbs va and a', thereby energizing the relay /z and causing thesame to attract the. armature thereofl to thus maintain the circuitthrough lamp m' open. The circuitY through the lamp 711/, which wasclosed by the removal of the plug p from its seat, is thus opened, andthe lamp is thus eX- tinguished. The operator now bridges her telephoneset in circuit and having learned the number ofthe called subscriberlifts the calling-plug o and touches the tip r/ thereof to the test-ringto determine whether or not the line of subscriber B called for is busy.1f

subscriberB is busy, his relay I) will be ener-J gized and springthereof will rest against contact 6. Upon touching the tip of thecalling-plug to the test-ring the operator will he'ar a click in hertelephone if the line is busy and the relay energized; otherwise hertelephone Will remain silent. rlhis click is caused by the fact thatbefore the tip is touched to the testring the point where the operatorstelephone set is connected with thestrand t is of the same potential asthe battery fr', since the battery is on open circuit. When, however,the tip is touched to the test-ring, the circuit of battery 1" is closedfrom ground through winding w3, strand t', tip 0, test-ring d'5, contact6, spring to ground, and due to the fact that the winding w3 isinterposed between the pole of the battery and the point where thetelephone set is connected with the strand t the potential at this pointof connection will be lowered andl a current will thus How throughingcurrents from ground through generatori g`,strand t', limb a, throughsubscribers bell vf5, to ground. The' bell of subscriber B is thusactuated,.and when subscriber B removes 'his telephone-receiver from'the hook, `limbsu a are closed together at the substation. The circuitof battery r is thus closed through rclay over strands z," s and limbsau of substation B. When the operator removes the calling-plug o fromits seat, the circuit through IOO IIO

.-eithe telephonefreceiver of either subscriber c Alamp ml. 4 spring mmakes contact with contact 13, thus c lamp e is closed and ythe lamp islighted. When the called subscriber responds and lifts his telephonefrom the hook, thus closing the circuit oi' battery fr through relay 7c,the spring 117 is separated from contact 15', thus opening the circuitthrough lamp e .and extinguishing the same. i

lhe talking-circuit is shown in diagram in Fig. 3. r1`he variation 4ofresistance caused by the operation of the microphone of subscriber cAvaries the'current delivered by battery fr, thus causing a vibrating lcurrent to traverse the windings 'zu' and 'wzof relay w,thereby inducingcorresponding current in the windl ings w3 and uf, which traverse thereceiver of subscriber B. Likewise vibratory currents produced by themicrophone of subscriber B are transmitted to `the'freceiver ofsubscriber` A'fVVhen the subscribers have completed theirconversation,they hang up their tele?,kv phone-receivers, and the limbs t a/ arethusA separated at the substation. Thus when sub-` scriber A hangsup histelephone-receiver the limbs (t a are separated at the substation andthe circuit of battery 0' through relay is opened, thereby deenergizingsaid relay and ,permitting spring 'In to engage contact 13 to `thusclose circuit through lamp fm.' and light Similarly the hanging up'ofthe c the same.

V`receiver of subscriber B lights the lampo'.

The lamps thus remain lighted until the plugs have been returned totheir respective seats. Thus when plug pis returned to its seat springm2 is separatedfrom contact 14, thereby opening the .circuit throughlamp m and eXtini guishing thesame. Likewise the return of plug o to itsseat extinguishes lamp o. The

lamp of the called subscriber is thus lighted as soon as ,connection ismade with his line and is extinguished as soon as he removes histelephonefreceiver from the hook,`thereby1 giving the operator thesignal that the subscribers are in conversation. The hanging up lightsthe lamp corresponding' thereto to thereby indicate to the operator thatdisconj nection is desired. Either subscriber may by vibrating hisswitch-hook alternately light and extinguish his lamp'to indicate in theusual manner a desire for reconnection.

`In Fig. `4 I have 'illustrated a modification,

oi' the signaling-circuit- The relay Ii instead of being provided with aback contact isprovided with a Jfront contact, the spring m and contacty lbeing connected with opposite sides of the lV hen the relay isenergized, the

short-circuitinng thei lampV and extinguishing the same. '1n thismodiiication therelay when energized closes together its contacts to eXtinguish the lamp, `while in the form above described therelay whenenergized separates these contacts to extinguish the lamp. A re-`sistance 71,2 prevents the short-circuiting of the -battery when thelamp is .cut out. rlhis arlrangement does away w'ith the necessity of aback-contact relay.

I disclaim herein thematter claimed inthe p patent to Francis W. Dunbarfor telephoneswitcliboard systems, dated ANovember 12,

Having described my invention, what l claim as new, and desire to secureby Letters Patent, is-

1. The combination with a pair of telephone: lines, of a cord-circuittoloop said lines to-4 gether tor conversation and having a connect-Vphone-lines, of a cord-circuit to loop any ot' said ,lines together inpairs for conversation and havingr a connecting-plug at each end, a pairof sources of electricity, one for each line of each connectedpair, andAplaced in circuit therewith by the act of connecting the cordcircuit'with the lines, a relay associated with each end of the cord-circuitand operatedover the 'metallic telephoneline from the correspondingsource of current, a plug-seat switch `for each plug, and a supervisorysignal for eacliend of the cord-circuit controlled by the conjointactionA of the relay and plug-seat switch associated with thecorresponding end of thecord-circuit, substantially as described. 3..The combination with a plurality of telephone-lines, of5a cordcircuit toconnect any of said lines together in pairs for conversation and havingconnecting-plugs, a pair oi sources IOO i iko of electricity one foreach line of each connected pair and` placed in circuit therewith by theact of connecting the cordcircuit with the lines, the ends of saidcord-circuitbeing inductively united together but conductivelydisconnected@ relay associated with each end of the cordrcircuit andoperated over the telephone-line from the corresponding source oi'current, a plug-seat `switch for each plug of the cord-circuit, and asupervisory signal for each end ofthe cord-circuit, controlled by theconjoint action of the relay and plug-seat switch associated with thecorresponding end of the cord-circuit, said signal being actuatedwhenever the relay is deenergized and the plugis out of the seat andrendered inoperativewh'enei'fer the plug '1s in its seat or there- `layenergized,substantially as described.

, 4. i The combination with a plurality ot' telephone-lines, ofacord-circuit to connect any Alao of said lines together in pairs forconversation and having connecting-plugs, means Vto conductivelyseparate but to inductivelyjoin the ends of said cord-circuit, a pair ofsourcesof electricity, one bridged across each'end of the cord-circuitand adapted to be included inthe metallic telephone-line when aconnection is established, a relay for each end oi' the cordcircuit andin the path of current overthe me-A tallic line, a plug-seatswitch foreach plug,.

and a supervisory signal for each plug having its circuit controlled bythe `corresponding switch and by said relay and so that the signal isactuated when the plug is out of its aseat 'and the relay denergized andis rendered'inoperative at other times,l substantially as described. ,tY

5.` The combination with a plurality of'telephone-lines, of acord-circuit to connect said lines in pairs for conversation, saidcord-circuit being provided with connecting-plugs, a repeating-coilinterposed between said plugs to inductively unite the same together andto conductively separate them, a separate source of current. associatedwith` each end of the cord-circuit and adapted to send current over themetallic telephone-lines when a connection is established, a relay foreach endl of thecordcircuit. in they ath of current over the metallictelephone-ine, a plug-seat switch for each plug, and a supervisorysignal for each plug having .its circuit controlled. by the corresponding switch and relay, substantially as described. y I* I 6. Thecombination withza plurality of telephone-lines, of a cord-circuitctoconnect said cuit and between the windings of. said repeatc ing-coil, arelay associated with each end of the-cord-circuit and in one strandthereof, said relay being in the path of current over themetallictelephone-line, a plug-seat switch associated `with each end ofthe cord-circuitifor the connecting-plug, and a supervisory signal foreach plug having its local circuit controlled 4, by the correspondingrelay and plug seat n switch, substantially as described.

- 7. The combination with a plurality of telephone-lines, of a cord tovariously loop said lines together for conversation and having aconnecting-plug at each end, said cord-circuit having only twostrandsand the ends thereorl being conductively discontinuous butinductivelyunited, a pair of sources of electricity associated with thecords and lines, one source being independently included in the circuitof each line during the connection, a separateV` yand independent relayassociated with each end of the cord-circuit and included in themetallic circuit with the corresponding source of current andtelephone-line when a connection is established, and a. supervisorysignal for each end of' vthe cord-circuit controlled during conversationby said relay, substantially as described.

8. The combination with a plurality of telephone-lines, of acord-circuit to connect any of said lines together in pairs forconversation and having a connecting-plug for each end, meanstoconductively separate but inductively unite the said ends of thecord-circuit, a pair of sources oi' electricity, one bridged across eachend of the vcord-circuit and adapted to be included in Vthe metalliccircuit with the corresponding telephone-line when a connection isestablished, a separate and independent relay for each end of thecord-circuit and in the path of current over 4 the said correspondingmetallic telephone- ',line, and a supervisory signal associated witheach connecting-plug and controlled during conversation by thecorresponding relay, substantially as described.

9. The combination with a plurality of telephone-lines, of acord-circuit toconnect any of said lines together in. pairs forconversation and having a connecting-plug for each end, means to'conductively separate but inductiv ely unite the said ends of thecord-circuit, a pair of'lsources of electricity, one bridged across eachend oi' the cord-circuit and adapted to be included in the metalliccircuit With the co1 responding telephone-line when a connection isestablished, a separate and independent relay for each end of thecord-circuit and in the path of current over the said correspondingmetallic telephone-line, a supervisory signal associated with each ofthe connecting-plugs, a local circuit for each said signal, saidcircuits being controlled at one point by the corresponding relays andat another point by auxiliary means, substantially as described.

10. The combination with 'a plurality of telephone-lines, of acord-circuit to connect any of said lines together in pairsv forconversation andhaving a connecting-plug for each end, means toconductively separate but inductively unite the said ends of' thecord-circuit, a pair of sources of electricity one bridged across eachend of the cord-'circuit and adapted to be included in themetallic-circuit with the' corresponding telephone-line when aconnection Iis established, a separate and independent 'relay for eachend ofthe cord-circuit and in the path of current'over the saidcorresponding metallic telephone-line, a supervisory signal foreach endof the cord-circuit, local circuits for saidsignals, said relays serv-Aing when actuated to open said local circuits at one point to renderthe said signals inert during conversation, and other means to close-said circuits when the plugs are connected with thelines so that thesaid lsignals may be operated when the subscribers telephonesr are IOOIOS

not in use, and to open the same when the plugs have been disconnectedfrom the lines so that the said signals are again rendered inert,substantially as described.

ll. rIlhe combination with a plurality of tele-4 phone-lines, of acord-circuit to connect any of said linestogether in pairs forconversation and having a connecting-plug for each end,

means to conductivelyseparate but inductively unite the said ends of thecord-circuit, a pair of sources oi' electricity, one bridged across eachend of the cord-circuit and adapted to be included in the metalliccircuit with the corresponding telephone-line when a connection isestablished, a separate and independent relay for each end of thecord-circuit and in the path of current over the said correspondingmetallic telephone-line, a supervisory signal associated with each plug,means controlledn nesses.

'- KEMPSTER B. MILLER.

Witnesses:

W. CLYDE JONES,

M. R. NYMAN.

